I wonder just how much bandwidth the eDRAM has... At the very least it has to be over 20GB/sec to match the Wii's 3MB + 24MB 1T-SRAM aggregate bandwidth, but that's still slow for a modern HD system.
I wish a dev would just leak the specs somewhere they're unlikely to be traced.
wouldn't edram be in the high tens of GB/s if not higher?
plus if exploited well, its not only faster, but removes reads/writes to main memory too, which puts less burden on the main memory (so you can 'get away' with slower ram)
eg fetch texture from main memory, fuck about with it in the GPU, then write it back to main memory (frame buffer), and eventually write to the screen
with edram you can grab the texture (one hit on main memory), fuck about with it, write it to edram frame buffer (or working space too hopefully), then write to the screen. assuming you do that a ton of times per frame, it can be a big advantage.